Art of Assembly Language, 1st Edition

5.16. 5.16 Low Level Implementation of Automatic (Local) Variables

Your program accesses local variables in a procedure using negative offsets from the activation record base address (EBP). Consider the following HLA procedure (which, admittedly, doesn't do much other than demonstrate the use of local variables):

procedure LocalVars; @nodisplay;
var
     a:int32;
     b:int32;
begin LocalVars;

     mov( 0, a );
     mov( a, eax );
     mov( eax, b );

end LocalVars;

The activation record for LocalVars appears in Figure 5-6.

Figure 5-6. Activation Record for LocalVars Procedure.

The HLA compiler emits code that is roughly equivalent to the following for the body of this procedure: ...